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Thread: Valve Stem Seal DIY with AGA tool set - helpful tips

  1. #1
    Join Date
    Mar 2017
    Location
    Glendale, CA
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    7
    My Cars
    2006 BMW 750i

    Valve Stem Seal DIY with AGA tool set - helpful tips

    I am an avid BMW DYI enthusiast, working on several cars over the decades, now in my sixties. Below are some useful tips for those of you contemplating doing the BMW N62 valve stem seal replacement using the AGA tool set, my experience garnered from recently doing the job myself. Recognize that ALL BMW V8 engines from 2006-09 (?) have or will have (60-120 K miles) this issue, and at some point you will fail the “check for smoke” hard rev done at the very end of a long idle smog test. Then you can junk your beautiful car for $1,700 since you will only get $3K for trade-in with this problem, and your lack of smog certificate and good conscience will not allow you to sell it privately. SO, you either pay a garage $4-8K to do the job, buy a new car with similar miles that is NOT a V8 for $20+K, or do it yourself! Here are my tips for using the AGA tool set, and doing it with the engine in my car, a 2006 BMW 750i:
    1. In general, this is a grueling (32-valve) job not for those with weak lower backs. You should allow 3 days for each side of the engine from start to finish. You can do one side at a time, reassemble, and test for smooth operation and valve cover gasket leaks if any. You may luck out and have one side (one or more valves on that side) being the main contributor to the smoke, and get through smog without doing the second side immediately. (I did driver side first, and passed smog before doing passenger side). Eventually of course, they’ll all leak.
    2. General preparation: Of course, you have ordered and have in hand your AGA tool set (~$900) your valve stem seals, and valve cover gasket sets. Have a variety of angled long-reach needle nose pliers, some moly grease, and especially small and large magnets on telescopic probes or flextures. You should have in hand a few spare keepers (I bought all new) in case you drop one under the car (make absolutely sure it’s not in the engine!) and your job cannot proceed without it! I also had two boxes (!) of vinyl gloves for several needed cigarette breaks along the way. After removing the plastic protection covers under the car front, then remove the heavy large metal plate (5 bolts about 5/8”). You will be glad to have done this, since all kinds of dropped items will end up there, and it’s also useful during the final checkout to help identify any oil leaks. If you have a good flexible length magnet, you may not need to remove this plate, and instead go fishing for lost items. Of course, you’ll remove front air filters and units to get socket drive in to crank engine. For the driver side you’ll need to remove the vacuum hose to the brake assist, and disconnect the power steering reservoir (remove the single main hose connection below and let steering fluid out the bottom, then you can push the whole reservoir to the front of the engine out the way. No real need to remove the oil dipstick tube, but removing the dipstick itself helps. When you disconnect the fuel line (gently pull out grey ring) tape the ends to avoid fumes. For the passenger side, getting the valve cover out is more difficult. You’ll need to loosen all bolts on the electrical box in the top corner, and remove a small holding bracket, so that you can slide the two umbilical harnesses with their grommets upward and then tie the harness as high as you can with a cable to the hood latch above. The ABS steel plumbing lines are a pain, but there’s only a little wiggle room there. For both sides, keep your eyes and fingers on the vertically protruding cam sensor body that you have to lift over since they are expensive if you break one. When you take out the variable lift motor(s) don’t get too surprised when on the final bolt it jumps out aggressively; that’s normal.
    3. The AGA tool video is great, but trust me it’s MUCH harder with the engine in the car. Expect to repeat various steps multiple times until they behave; be patient and determined. Although some valves (especially easier exhaust valves on lower row) go quite easily and quickly (15 mins), you will come across a few valve situations that can take an hour or more. It’s not unusual to wrestle with the tool-foot positioning until you get it seated right preparing for valve spring compression.
    4. The valve stem keeper install tool works perfectly every third attempt until you get the hang of it. Keepers will seem to disappear, and you find them with a small magnetic probe hiding in an oily corner. Keep track of them! Before installing the keepers into the tool, practice your run with the empty tool, since it is important to adjust the angle of the foot for each particular valve (different approach angles, etc). Do NOT be satisfied if you can’t find a lost keeper – it will wreak havoc to the engine if left there. The grease application is important since it helps the keepers stick to the valve stem, but a trick I learned is that if the keepers are mainly on but not quite, it’s OK to use a gentle finger or screwdriver to carefully nudge them together. They need to look perfectly married together (and really make sure you see BOTH of them) or they will not slide through and into the valve spring retainer-washer and give you problems.
    5. You MUST USE a leak-down tester (and not just an air compressor), since for the stage of spring compression on the naked stem as you ready to next install keepers, it is EASY to have the spring lean or nudge the valve stem, and the cylinder pressure drops suddenly. With a leak-down tester, you can also watch the leak pressure to know if this happens. Once it does, you have to go back to removing the spring and retainer and pulling the valve stem back up to reseal (verified on leak down tester pressure gauge). This happens typically a few times during each engine side, and is frustrating; again, be patient, and do it again.
    6. Grease up the inside of the compression spring retaining “washer” so that it seats on the wobbly spring without repeatedly slipping off. Once you have the compression spring installed, I threaded the retaining “washer” to the top of a long thin screwdriver, and let it slide down into the spring for preliminary mating.
    7. The lower exhaust valves are usually straightforward, but the intake valves can be a royal pain. For the intake valves, despite the AGA claim that you optionally can remove the larger variable lift rocker arms (intermediate levers) and it will just take you longer, you DO NOT WANT to remove them. It becomes a nightmare. Moreover, it’s VERY easy to lean on the top of them and have them slip down. If they slip or you need to re-install from scratch, you’ll need to make a couple of notched-blade screwdrivers (file the flat blade with triangular file) to attack the upper spring from below and above to reseat. As another video showed, it’s also easy to break the v-shaped locators at the bottom, right above the lower rocker arm, so do not force anything without watching carefully what you’re doing. Here’s my smart solution: Use about a 6-inch length of firm copper wire (I used a piece of coated wire stripped from a standard house electric Romex) to TIE UP the intermediate variable lift rocker arm. Push/feed the wire through the nearside of the spring and fish just below capturing the top cam piece, then twist hard with pliers and trim to absolutely hold that baby tight. This works great! It’s EXTREMELY important to first set top-dead-center TDC, THEN install ties on two intake valves. And it’s EXTREMELY important that you remove the wire ties (they feed through cam surface bearings!) BEFORE you move the engine to a new TDC position! Move slowly and carefully.
    8. Do not underestimate how stubborn the old stem seals can be to remove. Try to rotate/twist first before you pull on them. In a couple of instances, I had to use long 45 degree needle nose pliers. After wrestling with them for several minutes, they then suddenly and innocently slide out as if they were willing all along!
    9. CHECK that you’re at TDC for each cylinder you’re working on!! On one occasion, I foolishly went to a new cylinder without resetting TDC or moving over the compressed air line. (Yes, you can get that tired). Then after removing valve keepers and recompressing spring to install new keepers, the valve suddenly slid into the engine and I heard it ping on the cylinder top! And like a fool, I’d been watching the leak-down pressure thinking everything was OK (wrong cylinder!). If I peered through the valve guide, I could JUST see the end of the valve in the tunnel. Then I went from heart failure to ecstacy when I discovered that I the AGA magnet sleeve (used to protect new seal installation) was just small enough to enter the hole. By placing a larger magnet behind it for security, that little darling went in and held on to the top of the valve stem, and I carefully slid it up, grabbed it with surgical ratchet-clamp tweezers, and thanked the Lord.
    10. Although the job is daunting and you’ll oscillate between giving up and persevering, when you’re done after a few days, and the engine sounds great with no smoke and no oil leaks, you’ll suddenly feel like a King or Queen, your self-esteem will climb, and you’ll be so glad you did it- for the money saved, and for the pride gained. Your friends will say: “Gunga Din, you’re a better man (woman) than I”!

  2. #2
    Join Date
    Jun 2008
    Location
    Hamilton, Ontario, Canada
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    52
    My Cars
    2007 Alpina B7
    My hat is off to you, congratulations and kudos to you for doing the job yourself and writing it all up as well. Love your narrative and style.
    I am sure you will and have inspired many. Thank you
    Last edited by shogun; 10-10-2018 at 09:49 AM.

  3. #3
    Join Date
    Apr 2011
    Location
    columbus, ohio
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    E31, E65, F01
    Great write up. Just curious, knowing what you know having performed this job, what would someone need to charge you to make it worth not doing it yourself? Taking into consideration time, tools and parts? Reason I'm asking is I just purchased a 2006 750li and although the seals don't need to be replaced right now, they will need to be done eventually. Maybe a year or two down the road. I discussed this with the mechanic at the dealership where I purchased the car and got them to write into the sale an agreement to do the valve stem seal replacement for 2k when the time comes. This was after reviewing the procedure online and determining that I had the skills to do it but not the tools and really didn't want to mess around with the valve springs but if the alternative was a 4k-7k price tag to have an indy or BMW do it. I would do it myself.
    Last edited by toomann; 03-24-2017 at 11:55 AM.

  4. #4
    Join Date
    Mar 2017
    Location
    Glendale, CA
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    7
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    2006 BMW 750i
    An agreement to do it for $2K is almost unbelievable, since the AGA tool is $900, the stem seals (32) and 2 valve cover gaskets, plus new steering fluid, extra tools, etc etc will mean that the labor is virtually free! I would strongly advise you to get them to do it ASAP when you can be without the car for a few days, since the longer you wait (2 years between Smog tests), the more forgetful they will be, or have some hidden clause about a time limit. Make sure you understand if the $2K includes parts, etc as I'm sure you have. The DIY job is a little like being on the TV show "Naked and Afraid" since it's a grueling task (~5 regular workdays), but at the end of it you feel like you really achieved something. The minimum charge to avoid the DIY would depend on the value of ~5 days of your time under stressful body-wracking work.... so $4K may be the answer. I would be reluctant to have a non-BMW specialist do it, or go for a cheap offer, since it is tempting for someone other than yourself to NOT do the back valve or two, and a large part of the smoke can come from only one valve if severely worn.... Some other DIY reported that he didn't do 2 valves as "couldn't reach" but I worry that in the long term, doing less than 32 is like doing none. These cars are awesome, so good luck with your valve job; get it done sooner than later, and it will not be in the back of your mind.... Cheers
    Last edited by shogun; 10-10-2018 at 09:50 AM.

  5. #5
    Join Date
    Apr 2011
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    Thanks for your reply. "An agreement to do it for $2K is almost unbelievable" Was what I was thinking when it came out of the mechanics mouth. We discussed the job in full and this is a reputable dealership that has a long history of selling high performance cars. So I don't have any doubt about their ability to do the job. But when the mechanic dropped that price I immediately pulled the sales guy aside and offered to buy the car providing he was willing to put in writing that they would do the job "parts / labor" for 2k. He spoke with the sales manager and I actually wrote what I wanted the agreement to say and both the sales manager and I signed it. But your words of caution are well noted. But seeing that they have a good reputation I don't see them wanting to damage that by defaulting on a 2k service job. I can easily steer potential customers to them or away based on their keeping their end of the agreement. It's simply wouldn't be worth it for them. So for now I'm going to just enjoy the car. I only put 5k or 6k a year on my daily driver and told the mechanic and sales manager I would most likely bring the car in the next year and have it done. I have plenty of other cars to drive so that's not a concern. From my first car purchase I've never was comfortable depending on just one car and have always had a backup to drive. Early on (i'm showing my age) it was easy to pickup a dependable used car for less than a grand. And even easier since I've always done my own work on them ( Thanks Dad ). My fathers weekends were always filled with work on his car projects and friends cars that he would take on. So I happened to be his apprentice for many years.
    Last edited by shogun; 10-10-2018 at 09:51 AM.

  6. #6
    Join Date
    Mar 2017
    Location
    Glendale, CA
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    7
    My Cars
    2006 BMW 750i
    Sounds like you have a robust arrangement there, but certainly appreciate the detailed scope of the work to be done. As an addendum, I would point out that my last valve (passenger side, last intake to rear) I had a lot of trouble getting the keepers on in the very restricted space. I ended up filing some of the special tool rectangular base to give that extra millimeter of room, but ended up spending 3 hours on repeated attempts and nervously retrieving the fallen keepers with each failure. But again, in the end it's a great feeling to have done it since my beautiful car went from being worth $1,750 as salvage to ~$9,500 in current value.

  7. #7
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    You guys are funny. We still drop the motors out of the car to do the seals. Obviously, not everyone has the luxury of a lift and the tools that we have.
    ASE and BMW Master Certified Technician

  8. #8
    Join Date
    Mar 2017
    Location
    Sheboygan,wi
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    3
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    745li
    There is a guy that RENTE OUT THE AGA N62 VALVE STEM SEAL KIT, YOU CAN FIND THEM ON FACEBOOK "BMW AGA TOOL RENTAL " ITS ONLY FOR $280.00 THERE NUMBER IS 414/629/6459 JUST IN CASE ANYONE NEEDS IT. I used them and it worked out great

  9. #9
    Join Date
    Mar 2017
    Location
    Glendale, CA
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    7
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    2006 BMW 750i
    HaHa! We ARE funny, even crazy doing the challenging DIY jobs we take on. I guess it's a love-hate relationship! I'm originally from the UK, so to explain our behavior, please recall the quote that "Mad dogs and Englishmen go out in the midday sun"!

  10. #10
    Join Date
    Nov 2012
    Location
    CLE, OH
    Posts
    10
    My Cars
    750i, X5
    Does anyone have an AGA tool kit for sale?

  11. #11
    Join Date
    Jun 2018
    Location
    Li
    Posts
    5
    My Cars
    750ll
    Just heads up to everyone that plans on doing the valve stem seals. This video saved my life.
    I was very afraid to start the job , you after reading people dropping valves and becoming a nightmare. Well after i watched this video i found out there is a fb group as well from many people that have done the job them self. I called them up and got the tools and the seals from them. Man o man it gave me the confidence and i had no fear to get the job done.
    God blas tony for all the help. The small tricks and the details he gives out its just amazing. That guy knows this issues inside out. I had issues after the job and i had codes and i was able to get everything fixed right away with the fb grops help and tony.
    https://youtu.be/cFNfZaQLKno

  12. #12
    Join Date
    Mar 2017
    Location
    Glendale, CA
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    2006 BMW 750i
    Yes, the "rope" method of supporting the valves is very clever, and will save you the need to use a compressor/leak tester. Dayfixer provides YouTube link.

  13. #13
    Join Date
    Jan 2016
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    Ca
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    2001 525it
    When the kit came out, we called a Couple of the other well known independents to see if they had the tool and had been doing the job. Nobody had the tool and there customers didn't want to fork out the money to do it. Dropping the motor would be the best way.

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